Disclaimer: This presentation is prepared by trainees of baabtra as a part of mentoring program. This is not official document of baabtra –Mentoring PartnerBaabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt . Ltd

Control statement

in cShanu k kshanukk89@gmail.comwww.facebook.com/shanunnitwitter.com/shanuin.linkedin.com/in/shanu9656153432

• C provides two sytles of flow control:• Branching• Looping

If statement

• It takes an expression in parenthesis and an statement or block of statements. if the expression is true then the statement or block of statements gets executed otherwise these statements are skipped.

If(test expression)Statement;Or If (test expression){Block of statements1;}Else{Statement2;}

Switch statement

• A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each switch case.

Switch( expression){ case 1Statement 1Break;}Case2Statement 2Break;}

• Depending on the position of control statement in c,control structure may be classified

• Entry_ controlled loop• Exit _controlled loop

False

true

Entry controlled loop exit controlled loop

Test conditio

n ?

Body of the loop

Body of the loop

Test conditio

n ?

• C language provides three constructs for perfoming loop operations

• While statement

• Do statements

• For statements

While(test condition){

body of the loop}

……………………… ……………………… int_sum=0; int_n=1; while(int_n<=10) { int_sum=int_sum+int_n; int_n=int_n+1; } printf(“sum=%d\n”,int_sum); …………………………………………..

Do statement

do{ Body of the loop} While(test condition)

int_i=1; int_sum=0; do { int_sum=int_sum+I i=i+2; } while(sum<40||i<10); printf(“%d %d\n,I,sum);

For statements

For(intialization;testcondition;icrement){

body of the loop}

• Intialization of control variable done first using assignment statement• The value of control variable tested

using test condition,ie reletional expression such as i>10,that determine when the loop will exit• If the condition is true ,the body of

loop executed,otherwise terminated

int_sum=0; for(int_n=1;int_n<=10;int_n++) { int_sum=int_sum+int_n; } printf(“sum=%d\n”,int_sum);

additional features of for loop

1. More than one variable can be intialized atb a time2. More than one variable incremented at a time3. The thest condition may have compound relation4. One or more sections can be omitted ,if necessary eg: m=5; for(;m!=100;) { printf(“%d\n”,m) m=m+5; }

Nesting of for loop

For(i=0;i<n;i++){ ………………………………For(j=0;j<n-1;j++){ ………………………………}}

Jumping out of a loop

• Exit from a loop using break statement if a break statement encounteredd in a

loop,the loop will immidiatly exited and the program continues with the statement immidiatly following loop;ie break will exit only a single loop

Eg: while(test condition) { …………………………….. ……………………………… if(condition) break;

Skipping a part of loop

Another statement ‘continue’,• It tells the compiler skip the following statements

and continue with next iterationEg:While (test condition){………………………..If(…………)Continue;

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