The document discusses different control structures in C programming. It covers for, while, and do-while loops used for iterative execution. It also covers jump statements like continue, break, and goto that change the flow of execution. The for loop uses an initialization, condition, and increment/decrement. The while loop checks a condition before each iteration. The do-while loop checks the condition after executing the body. Continue skips to the next iteration. Break exits the current loop or switch. Goto jumps to a labeled statement.

1. Lecture05(Control Structure PART-II)
June 27, 2010
Today's Outline
Looping statements in C
• for loop
• while loop
• do-while loop
Jump Statements in C
• continue
• break
• goto
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2. for loop
General Format:
for( initialization; condition; increment/decrement )
{
statements; //body of the loop
}
Init
false
Condition
true
Body of loop
Inc / Dec
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3. for loop (Cont.)
Example:
int sum = 0, count;
for(count = 1; count <= 5; count++)
sum = sum + count; //body of the loop
printf("%d", sum);
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4. while loop
General Format:
while( condition )
{ Condition
false
statements; //body of the loop
true
}
Body of loop
int sum = 0, count;
count = 1;
while( count <= 5)
{
sum = sum + count;
count++;
}
printf("%d", sum);
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5. do while loop
Format:
do
{
Body of loop
statements; //body of the loop
}while( condition );
true
Condition
int sum = 0, count;
false
count = 1;
do
{
sum = sum + count;
count ++;
}while( count <= 5);
printf("%d", sum);
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6. loop (cont.)
• Loop
– Group of instructions computer executes repeatedly while some
condition remains true
• Counter-controlled repetition
– Definite repetition:
– Known in advance how many times loop will execute
– Control variable used to count repetitions
• Sentinel-controlled repetition
– Indefinite repetition
– Used when number of repetitions not known in advance
– Sentinel value indicates "end of data"
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7. continue
Skips the remaining statements in the body of a while, for or do…while
statement and proceeds with the next iteration of the loop
– while and do…while
• Loop-continuation test is evaluated immediately after the continue
statement is executed
– for
• Increment/ decrement expression is executed first, then the loop-
continuation test is evaluated
int i, sum = 0;
for(i=0; ;i++)
{
if(i%2==1)
continue;
sum += i;
}
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8. break
• Causes immediate exit from a while, for, do…while or switch
statement.
• Program execution continues with the first statement after the control
structure.
• Common uses of the break statement
- Escape early from a loop
- Skip the remainder of a switch statement
int i, sum=0;
for(i=1; ; i++)
{
sum += i;
if(sum >= 10)
break;
}
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9. goto Statement
Format:
goto label;
main()
.........
{
.........
double x,y;
label:
read:
statements;
scanf("%lf",&x);
if(x<0)
label: goto read;
statements; y=sqrt(x);
......... printf("%lf",y);
......... }
goto label;
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10. Any Question?
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11. Thank You All
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