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Lecture15 comparisonoftheloopcontrolstructures.ppt
The document compares and contrasts the three main loop control structures in C programming: for loops, while loops, and do-while loops. It outlines the key differences in how each loop is initialized, how the condition is evaluated, and where increment statements are located. The break and continue statements are also briefly explained regarding how they allow early termination or skipping iterations of a loop.
Lecture15 comparisonoftheloopcontrolstructures.ppt
- 1. Comparison of theloop control structures Prakash Khaire B V Patel Inst. of BMC & IT, GopalVidyanagar
- 2. for while do…while A for loop is used to A while loop is used to A do while loop is used to execute and repeat a execute and repeat a execute and repeat a statement block depending statement block depending statement block depending on a condition which is on a condition which is on a condition which is evaluated at the beginning evaluated at the beginning evaluated at the end of the of the loop. of the loop. loop. Example : Example Example for(i=1; i<=5; i++) i=1; i=1; { while(i <=5 ) do s = s + i; { { p = p * i; s = s + i; s = s + i; } p = p * i; p = p * i; i++; i++; } }while(i<=5);
- 3. for while do…while A variable value isA variable value isA variable value is initialized at the beginninginitialized at the beginninginitialized before the loop of the loop and is used inor before the loop and isor assigned inside the loop the condition. used in the condition. is used in the condition. A statement to change theA statement to change theA statement to change the value of the condition or tovalue of the condition or tovalue of the condition or to increment the value of theincrement the value of theincrement the value of the variable is given at thevariable is given inside thevariable is given inside the beginning of the loop. loop. loop. The statement block will The statement block willThe statement block will not be executed when thenot be executed when thenot be executed when the value of the condition isvalue of the condition isvalue of the condition is false. false. false, but the block is executed at least once irrespective of the value of the condition
- 4. for while do…while A for loop is commonlyA while loop is also widelyA do-while loop is used in used by manyused by manysome cases where the programmers. programmers. condition need to be checked at the end of the loop.
- 5. break Statement * Thebreak statement, when executed in a while, for, do/while, or switch structure, causes immediate exit for that structure. * Program execution continues with the first statement after the structure. * Common uses of the break statement are to escape early from a loop, or to skip the remainder of a switch structure
- 6. Continue Statement * Thecontinue statement, when executed in a while, for, or do/while structure, skips the remaining statements in the body of that structure, and proceeds with the next iteration of the loop. * In while and do/while structures, the loop- continuation test is evaluated immediately after the continue statement is executed. * In the for structure, the increment expression is executed, then the loop- continuation test is evaluated.
- 7. #include <stdio.h> #include<stdlib.h> int main () { unsigned x; x = 0; while (x < 10) { ++x; if (x % 2 == 0) { continue; } printf ("%i is an odd number.n", x); } return 0; }