Flipp Book Class-7

d. ……………………………………………… ……………………………………………… P ……………………………………………… A ……………………………………………… T ……………………………………………… A N ……………………………………………… ……………………………………………… ................................................................ Points to Know • Stepwise directions given to the computer in the language which they under stand is known as a Program. • Loping refers to repeat a task for specified number of times in the program. • The statement which is used to repeat a task during the program execution is called loop statement. • Pre-Test loop structure controls the loop in the entry point. • Post Test structure controls the loop in the exit point. • The functions which are attached and ready to use in the QBASIC system is called library functions. Terms to Know Looping : Repeat again and again Condition Library Function : Something that limits or restricts something else Statement : Ready made instruction comes with Q-basic. : Something that you say or write which gives information in a for- mal or definite way. Smart Computer Science Book-7 245

Worksheet Objective Questions 1. Fill in the blanks: a. .............................. refers to repeat a task for specified number of times. b. .............................. used in the test condition must be initialized before start- ing loop. c. Pre-test structure of loop controls the loop in the .....................point. d. Post-test structure of loop controls the loop in the ....................point. e. .............................. functions are ready made function come with QBASIC sys- tem. 2. State wether the following statements are True or False. a. Loop statement allows to repeat only one statement. b. STEP command is used to only increase or decrease to value of control variable. c. Initial value of loop always goes to smaller to bigger. d. String expression can not be used in the test condition. e. The body of the loop must change the value of the variable used in the test condition. Descriptive Questions 1. Answer the following questions: a. What do you mean by looping? b. What does loop statement do? c. Differentiate between WHILE-WEND and DO-LOOP statement. d. Differentiate between Pre-test and Post Test. e. Differentiate between WHILE condition and UNTIL condition. f. What do you mean by library function? 246 More on Qbasic

Logical Questions Output Output 1. Write the output : Output a. CLS Output W$ = \"PATAN\" FOR I = 1 TO LEN(W$) STEP 2 PRINT LEFT$(W$, I) NEXT I END b. CLS W$ = \"PATAN\" FOR I = LEN(W$) TO 1 STEP -2 PRINT LEFT$(W$, I) NEXT I END c. CLS W$ = \"PATAN\" FOR I = LEN(W$) TO 1 STEP -2 PRINT RIGHT$(W$, I) NEXT I END d. CLS W$ = \"PATAN\" FOR I = 1 TO LEN(W$) PRINT RIGHT$(W$, I) NEXT I END Smart Computer Science Book-7 247

e. CLS Output W$ = \"PATAN\" Output FOR I = 1 TO LEN(W$) Output PRINT MID$(W$, I, 1) NEXT I END f. CLS W$ = \"PATAN\" T = 20 FOR I = LEN(W$) TO 1 STEP -1 X$ = MID$(W$, I, 1) PRINT TAB(T); X$ T=T-1 NEXT I END g. CLS W$ = \"PATAN\" FOR I = 1 TO LEN(W$) X$ = MID$(W$, I, 1) PRINT TAB(I); X$ NEXT I END 248 More on Qbasic