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EEE 243B Applied Computer Programming Strings
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Example #1 Write code to take a first name and last name and create a new string with the full name first is “Daffy”, last is “Duck” fullName is “Daffy Duck”
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Solution Example #1 #include int main(void) { char firstName[15] = "Daffy"; char lastName[15] = "Duck"; char fullName[20]; strcpy(fullName,firstName); strcat(fullName, lastName); printf("The full name is %s\n",fullName); return(0); }
![Solution Example #1 #include int main(void) { char firstName[15] = Daffy ; char lastName[15] = Duck ; char fullName[20]; strcpy(fullName,firstName); strcat(fullName, lastName); printf( The full name is %s\n ,fullName); return(0); }](http://images.slideplayer.com/10/2811709/slides/slide_3.jpg "Solution Example #1 #include int main(void) { char firstName[15] = Daffy ; char lastName[15] = Duck ; char fullName[20]; strcpy(fullName,firstName); strcat(fullName, lastName); printf( The full name is %s\n ,fullName); return(0); }")
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Example 2 What is the output from the following code? char player[15]; strcat(player,"Wayne"); strcat(player,"Gretzky"); printf("Player#1: %s\n",player); strcat(player,"Mark"); strcat(player,"Messier"); printf("Player#2: %s\n",player);
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Solution Example 2 May have unexpected results since player is not initialized Ifchar player[15]=""; Player1: WayneGretzky Player2: WayneGretzyMarkMessier (OR may crash the system since has more than 15 characters)
![Solution Example 2 May have unexpected results since player is not initialized Ifchar player[15]= ; Player1: WayneGretzky Player2: WayneGretzyMarkMessier (OR may crash the system since has more than 15 characters)](http://images.slideplayer.com/10/2811709/slides/slide_5.jpg "Solution Example 2 May have unexpected results since player is not initialized Ifchar player[15]= ; Player1: WayneGretzky Player2: WayneGretzyMarkMessier (OR may crash the system since has more than 15 characters)")
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Example 3 Consider the 2-D array of names Write the code to find 1.the first name in alphabetical order 2.the last name in alphabetical order Hint: Use the strcmp function char greatOilers[7][15] = { "Gretzky", "Messier", "Smith", "Coffey", "Smyth", "Kurri", "Fuhr" };
![Example 3 Consider the 2-D array of names Write the code to find 1.the first name in alphabetical order 2.the last name in alphabetical order Hint: Use the strcmp function char greatOilers[7][15] = { Gretzky , Messier , Smith , Coffey , Smyth , Kurri , Fuhr };](http://images.slideplayer.com/10/2811709/slides/slide_6.jpg "Example 3 Consider the 2-D array of names Write the code to find 1.the first name in alphabetical order 2.the last name in alphabetical order Hint: Use the strcmp function char greatOilers[7][15] = { Gretzky , Messier , Smith , Coffey , Smyth , Kurri , Fuhr };")
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Solution Example 3 #include int main(void) { char greatOilers[7][15] = { "Gretzky","Messier", "Smith", "Coffey", "Smyth", "Kurri", "Fuhr" }; char first[15]; char last[15]; int cnt =0, numPlayers=7; strcpy(start,greatOilers[0];) strcpy(last,greatOilers[0];) for (cnt=1; cnt<numPlayers; cnt++) { if (strcmp(start,greatOilers[cnt] < 0) strcpy(first, greatOilers[cnt]); if (strcmp(last,greatOilers[cnt] > 0) strcpy(last, greatOilers[cnt]); } printf("In Alphabetical Order: First: %s Last: %s\n", first, last); return(0); }
![Solution Example 3 #include int main(void) { char greatOilers[7][15] = { Gretzky , Messier , Smith , Coffey , Smyth , Kurri , Fuhr }; char first[15]; char last[15]; int cnt =0, numPlayers=7; strcpy(start,greatOilers[0];) strcpy(last,greatOilers[0];) for (cnt=1; cnt<numPlayers; cnt++) { if (strcmp(start,greatOilers[cnt] < 0) strcpy(first, greatOilers[cnt]); if (strcmp(last,greatOilers[cnt] > 0) strcpy(last, greatOilers[cnt]); } printf( In Alphabetical Order: First: %s Last: %s\n , first, last); return(0); }](http://images.slideplayer.com/10/2811709/slides/slide_7.jpg "Solution Example 3 #include int main(void) { char greatOilers[7][15] = { Gretzky , Messier , Smith , Coffey , Smyth , Kurri , Fuhr }; char first[15]; char last[15]; int cnt =0, numPlayers=7; strcpy(start,greatOilers[0];) strcpy(last,greatOilers[0];) for (cnt=1; cnt<numPlayers; cnt++) { if (strcmp(start,greatOilers[cnt] < 0) strcpy(first, greatOilers[cnt]); if (strcmp(last,greatOilers[cnt] > 0) strcpy(last, greatOilers[cnt]); } printf( In Alphabetical Order: First: %s Last: %s\n , first, last); return(0); }")
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Summary 'C' strings are allocated to have a fixed maximum length Be careful when using strcat Use strcpy when appropriate Initialize empty strings to \0 ("") Many more useful string function strlen, strncpy, strncat, strcasecmp, strcoll See glib manual on website
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Solution 2 #include int main(void) { char mystr1[] = "What happens to this memory"; char player[16]; char mystr2[] = "Is this memory corrupted"; //strcat(player,"Wayne"); strcpy(player,"Wayne"); strcat(player,"Gretzky"); printf("Player#1: %s\n",player); printf("mystr1 = %s\n\n",mystr1); printf("mystr2 = %s\n\n",mystr2); strcat(player,"Mark"); strcat(player,"Messier"); printf("Player#2: %s\n",player); printf("mystr1 = %s\n\n",mystr1); printf("mystr2 = %s\n\n",mystr2); printf("Addresses: %i %i %i\n", (int) mystr1, (int) player, (int) mystr2); getch(); return(0); }
![Solution 2 #include int main(void) { char mystr1[] = What happens to this memory ; char player[16]; char mystr2[] = Is this memory corrupted ; //strcat(player, Wayne ); strcpy(player, Wayne ); strcat(player, Gretzky ); printf( Player#1: %s\n ,player); printf( mystr1 = %s\n\n ,mystr1); printf( mystr2 = %s\n\n ,mystr2); strcat(player, Mark ); strcat(player, Messier ); printf( Player#2: %s\n ,player); printf( mystr1 = %s\n\n ,mystr1); printf( mystr2 = %s\n\n ,mystr2); printf( Addresses: %i %i %i\n , (int) mystr1, (int) player, (int) mystr2); getch(); return(0); }](http://images.slideplayer.com/10/2811709/slides/slide_9.jpg "Solution 2 #include int main(void) { char mystr1[] = What happens to this memory ; char player[16]; char mystr2[] = Is this memory corrupted ; //strcat(player, Wayne ); strcpy(player, Wayne ); strcat(player, Gretzky ); printf( Player#1: %s\n ,player); printf( mystr1 = %s\n\n ,mystr1); printf( mystr2 = %s\n\n ,mystr2); strcat(player, Mark ); strcat(player, Messier ); printf( Player#2: %s\n ,player); printf( mystr1 = %s\n\n ,mystr1); printf( mystr2 = %s\n\n ,mystr2); printf( Addresses: %i %i %i\n , (int) mystr1, (int) player, (int) mystr2); getch(); return(0); }")
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Output and Explanation Overwrites memory allocated before the string String and addresses show below
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