CZ1003 Tutorial 4 - Character Strings in c programming PDF

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CZ1003 Tutorial 4 - Character Strings in c programming
String declaration, initialization, and operations
string input and output
string function
ctyphe.h character function
string to number conversion
formatted string i/o
Array of character strings...

Description

Tutorial4–CharacterStrings 1. Whatdoesthefollowingprogramprint?  #include #include #defineM1“Howareya,sweetie?” charM2[40]=“Beattheclock.”; char*M3=“chat”;  intmain() {  charwords[80],*p; printf(M1); puts(M1); puts(M2); puts(M2+1); fgets(words,80,stdin); /*userinputs:winatoy.*/ if(p=strchr(words,'\n'))*p='\0'; puts(words); scanf(“%s”,words+6); /*userinputs:snoopy.*/ puts(words); words[3]=‘\0’; puts(words);  while(*M3)puts(M3++);  puts(‐‐M3);  puts(‐‐M3);  M3=M1;  puts(M3);  return0; }  2. The following unknown function receives a string argument and a character argument, modifies the string argument and returns an integer value. Describe the purpose of the function.Giveanexampletosupportyouranswer.  intunknown(charstr[],charc) {  intx,y=0,z=0;    for(x=0;str[x]!=‘\0’;x++)   if(str[x]!=c)    str[y++]=str[x];   else    z++;  str[y]=‘\0’; returnz;

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} 3. Writethefunctionstrncpy()thatcopiesnotmorethanncharacters(charactersthatfollowa null characterare notcopied)fromthe arraypointedtobys2 to the arraypointedtobys1. If the array pointed to by s2 is a string shorter than n characters, null characters are appended to the copy in the array pointed to by s1, until n characters in all have been written.Thestrncpyreturnsthevalueofs1.Thefunctionprototypeis: 

char*strncpy(char*s1,char*s2,intn); 

WriteaCprogramtotestthefunction. Somesampleinputandoutputsessionsaregivenbelow: (1)TestCase1 Enterthestring: Iamaboy. Enterthenumberofcharacters: 7 stringncpy():Iama (2)TestCase2 Enterthestring: Iamaboy. Enterthenumberofcharacters: 21 stringncpy():Iamaboy.  4. WriteaCfunctionthatcomparesthestringpointedtobys1tothestringpointedtobys2.If thestring pointedtobys1isgreaterthan, equalto,orlessthanthestring pointedtobys2, then it returns 1, 0 or –1 respectively. Write the code for the function without using the standardCstringlibraryfunctionstrcmp().Thefunctionprototypeisgivenasfollows: 

intstringcmp(char*s1,char*s2); WriteaCprogramtotestthefunction. Somesampleinputandoutputsessionsaregivenbelow: (1) TestCase1: Enterasourcestring:abc Enteratargetstring:abc stringcmp():equal (2) TestCase2: Enterasourcestring:abcdefg Enteratargetstring:abcde123 stringcmp():greaterthan (3) TestCase3: Enterasourcestring:abc123 Enteratargetstring:abcdef stringcmp():lessthan (4) TestCase4: Enterasourcestring:abcdef Enteratargetstring:abcdefg

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stringcmp():lessthan 

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